Student or Learner
I read the following explanation of using 'on' and 'in':
Nouns denoting enclosed spaces, such as a field or a window, take both on and in. The prepositions have their normal meanings with these nouns: on is used when the space is considered as a surface, in when the space is presented as an area:
The frost made patterns on the window. (surface)
A face appeared in the window. (area)
I still don't understand what 'area' means here? Can I say: The frost made patterns in the window.
Frost patterns are on the surface of the window. You can scrap them off with your fingernail.
A face appeared in the window.
In this case it looks like the face is inside the window glass. It is similar to looking into a mirror. A mirror appears to have 3 dimensions so we say the reflection is in the mirror
So to answer your question, no you cannot say - The frost made patterns in the window.